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Results for “Caloric Tests”

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At least 865 records · Page 48Linked to original sources
PubMed1982

Floccular inhibition of the vestibulo-ocular reflex in man.

The vestibulo-ocular reflex (VOR) plays a major role in ocular motility. Stimulation of each semicircular canal produces excitation of a specific extraocular muscle and inhibition of its antagonist in each eye. Floccular inhibition of the VOR has been extensively studied in the rabbit. Inhibitory projections from floccular Purkinje cells reach the ipsilateral vestibular nucleus via the restiform body and selectively control certain VORs. We examined the ocular functions in a patient with a lateral lower pontine infarct that included the restiform body. The patient exhibited unilateral, selective disinhibition of the VOR manifested by disconjugate upward rotatory drift of the eyes at the end of lateral eye movement towards the side of the lesion. He had marked directional preponderance on caloric testing. The same underlying mechanism which produced the biased VOR also appeared to affect target position determination in fast eye movements, resulting in lateropulsion of saccades and asymmetric OKNs. This is the first clinical case supporting the theory of selective cerebellar inhibition of the VOR.

Animals↗
PubMed1984

An algorithm for neurotologic disorders.

In the evaluation of patients with complaints of dizziness, hearing loss, and/or tinnitus, the primary objective is to determine the site of the lesion. An accurate localization of the lesion is important for selecting the most appropriate radiologic study. The information obtained from the vestibular and audiometeric evaluations identifies the site of the lesion accurately. For the vestibular evaluation we use photoelectric nystagmography (PENG) and the Torok monothermal differential caloric test. The initial audiometeric evaluation consists of a pure-tone audiogram and speech discrimination scores. Additional audiometric site-of-lesion tests and ABR are used selectively as the diagnostic yield of these tests does not significantly add to the information already obtained from the vestibular evaluation. If the lesion is suspected to lie in the middle ear or internal auditory canals, we use pluridirectional tomography. For further delineation of lesions confined to the internal auditory canal we use pneumo-CT. For suspected morphologic lesions of the posterior fossa we use thin-section CT with enhancement. Review has proved useful in defining petrous apex and skull base lesions. CT-rBBC studies have proved valuable in objectively demonstrating a deficient perfusion of the brain. The vascularity of certain lesions such as glomus tumors can be satisfactorily confirmed by this technique.

Adult↗
PubMed1994

[The interaction of vestibular inputs with differing orientations of the otoliths in a gravitational field].

In alert pigeons Columba livia effects of static tilts about fore-aft and binaural axes (angles of tilts: 30-40 deg) on neck and ocular nystagmus elicited by monaural galvanic stimulation of the lateral semicircular canals with sinusoidal currents (peak amplitudes: 20-100 microA; period: 35 sec) were investigated. It was shown that the same angles of the tilts elicited different changes of horizontal nystagmus parameters in different animals. In some of them changes of quantitative characteristics of opposite-directed nystagmus differed with signs. Data support the correctness of recently (Stolbkov, 1989) proposed scheme of forming vestibulomotor reactions, according to which signals from heterolateral vestibular nuclei, during nystagmus, which are integrated, contain both canal and otolith components independent of stimulus mode addressed to canals or otoliths (separately or jointly). Results suggest also that caloric test may be a source of incorrect conclusions concerning state of vestibular system during static tilts the responses of functionally asymmetric semicircular canals may be symmetric ones. Moreover data suggest that sensitivity of convergent vestibular neurons to the canal signals is different depending on separated or combined canal and otolith stimulations.

Animals↗
PubMed1994

[A case of Fisher's syndrome with upbeat nystagmus].

We reported a case of Fisher's syndrome with upbeat nystagmus. The syndrome manifested itself with the appearance of diplopia and ataxic gait preceded by cold-like symptoms. Although slight blephaloptosis, marked bilateral upward gaze palsy, and restricted abduction of the right eye were observed, light reflexes and Bell's phenomenon were normal. A slight decrease in the muscular power of the distal extremities, bilateral fingertip dysesthesia, and diminished sensation of vibration were observed. All muscle stretch reflexes were absent, and no pathologic reflexes were noted. Truncal ataxia and incoordination were observed. The cerebrospinal fluid showed albumino-cytologic dissociation. Upbeat nystagmus in five directions of gaze was recorded on the EOG, the smooth pursuit eye movement showed a staircase pattern, and dysmetria was present in the saccadic eye movement. The caloric test elicited a satisfactory response, but the visual suppression test produced poor suppression. Taken altogether, the test results suggest that the responsible lesions in this case were not only peripheral but also central, extending from the midbrain to the tegmentum pontis and the vestibulocerebellum.

Adolescent↗
PubMed1994

[Instrumental study of vertigo: when and how?].

Any case of vertigo and equilibrium disorder for which an origin is not rapidly determined requires exploration for diagnosis. This exploration comprises two parts: first, that of peripheral components, including a standard audiometric examination, completed by study of the evoked auditory potentials. This is followed by vestibular examination comprising at least caloric tests of both ears, usually associated with rotation tests; second, exploration of the central pathways, by electro-oculography, study of pursuit and saccadic movements. The techniques of posturography, especially dynamic posturography by the equi-test, allow determination of the role of the vestibular apparatus in equilibrium and to define the respective roles of the labyrinth, vision and sensitivity in equilibrium. The technique is rapidly developing and will no doubt include the study of coordination of head and eye movements, study of stabilisation of vision and the head, and in particular study of otolithic function.

Audiometry↗
PubMed1994

[Unilateral supranuclear abducens palsy in a pineal tumor].

A 13-year-old boy complained of frequent headaches and diplopia on rightward gaze. A CT scan demonstrated hydrocephalus and a non-homogeneous enhancing mass in the pineal area, leading to a diagnosis of pineal tumor. The physical examination revealed no abnormalities. On neurological examination, there were a right homonymous hemianopsia and slight choked disc in both optic fundi. His right eye was slightly adducted on primary gaze. On right lateral gaze, his right eye could not move beyond the midline and showed gaze paretic nystagmus, whereas his left eye could move fully in all directions. The abducens palsy could be overcome by the oculocephalic maneuver or caloric test. Interestingly, his right eye could abduct when his left eye was covered. From these finding, this was labelled a supranuclear abducens palsy. The convergent nystagmus was observed. Rightward OKN (quick phase to right) of the right eye was abolished with and without the left eye covered, while leftward OKN of the right eye was preserved. Pursuit to right was disturbed. After removal of the tumor, the gaze palsies disappeared. It is postulated that the supranuclear lateral gaze palsy was caused by impairment of supranuclear control by involvement of lateral gaze pathways to gaze center coursing near the oculomotor nucleus.

Abducens Nerve↗
PubMed1993

Cerebellar infarctions and 'vestibular neuritis'.

Consecutive subjects 50 to 75 years of age with sudden onset of vertigo but without cochlear or neurological symptoms were investigated with neuro-imaging techniques. Doppler sonography of the vertebral and carotid arteries and recording of voluntary saccades and pursuit eye movements, caloric, spontaneous, gaze and optokinetic nystagmus. Among those studied, 6 out of 24 subjects could be demonstrated to have cerebellar infarctions, another 2 subjects had occlusion of one vertebral artery. Caloric tests could not identify subjects with a cerebellar infarction whereas prominently reduced pursuit eye movements could. Subjects with cerebellar infarction either had a vertebral artery occlusion or prominent cardio-embolic risk factors. It is suggested that subjects with symptoms as vestibular neuritis should be investigated with pursuit eye movements and with at least standard ECG recordings.

Aged↗
PubMed1995

[A case of myotonic dystrophy with impairment of smooth pursuit eye movement].

We reported a 36-year-old woman of myotonic dystrophy with impairment of smooth pursuit eye movement. The patient, whose mother was also affected, had psychomotor retardation from childhood. DNA analysis by Southern hybridization technique showed large DNA fragment (14/8.6 kb). Oculomotor limitation and gaze nystagmus were not observed, and saccadic eye movements were normal. In electrooculography, smooth pursuit eye movements were impaired toward both directions, and interrupted by saccades. The caloric test elicited a satisfactory response, but the visual suppression test produced no suppression. CT scan displayed paraventricular low density area, and MRI showed the multiple foci of high signal intensity in the white matter on T2-weighted images. No changes were detected on CT or MRI in the brainstem and cerebellum. The lesions in the brain are considered to be correlated with smooth pursuit impairment.

Adult↗
PubMed1994

Sudden deafness from vertebrobasilar artery disorder.

Two cases are presented of sudden deafness with vertigo and/or dizziness, a 19-year-old male and a 54-year-old female. Their onset condition was considered to be caused by vascular disorders in the area of the vertebrobasilar artery, but they showed no signs of the central nervous system disorders. Case 1 suffered right sudden deafness just after a super selective embolization for the peripheral area of the right vertebral artery, and case 2, just after the accidental cutting of the left vertebral artery during the procedure of neurovascular decompression surgery. The neurotologic findings in these cases were almost the same and the common characteristics were (1) irreversible total deafness of the affected ear, (2) canal paresis in caloric test, (3) retrolabyrinthine disorder of the vestibular system detected by the galvanic test, and (4) no obvious findings of central nervous system disorders, such as eye movement disorder or ataxy. These findings indicate that the sudden deafness was attributable to localized embolism in the inner ear artery caused by thrombosis in the area of the vertebrobasilar artery.

Adult↗
PubMedDate not supplied

[The physiological functions of the vestibular apparatus].

Physiological functions of the vestibular apparatus were considered in terms of functional systems, permanent physiological activity and robot theories. A working hypothesis is assumed on vestibular receptor as a sensory detector of some functional systems of the body which enables creation of the internal coordinate system together with proprioreceptors of ocular, cervical, trunk and limb muscles, articular and tendinous receptors for adequate spacial perception via ocular and tactile analyzers; extrapolation of somatic responses. Vestibular reactions in disease and experiment are believed to be systemic responses primarily of functional and oculomotor systems. Isolation of vestibular afferentation from the total afferent flow is impossible already at the level of vestibular nuclei. Perspectives of further usage of rotatory and caloric tests for investigation of vestibular function are outlined.

Eye Movements↗
PubMed1996

Computerized electro-nystagmography.

A computerized electro-nystagmography (ENG) system was developed on the basis of a new idea for the performance of ENG. In this system, all the functions of conventional ENG was performed by a personal computer (PC) except for the initial setting of an analog amplifier. The eye movement signals from the ENG amplifier were displayed on the graphic screen and recorded on a magnetic or magneto-optical disc. By using a special graphic screen, eye movements, even fine nystagmus, can be more clearly observed than they can on the PC's conventional graphic screen. Examiners can select the most suitable display condition according to the specific purpose(s) of the ENG examination. As a laser printer prints the recorded eye movements simultaneously with data sampling, we can observe eye movements in the same manner as on the recorded paper of a conventional ENG. Moreover, this system has a very powerful function for the analysis of such nystagmus responses as caloric test, VOR test and optokinetic nystagmus and it can be gotten at a lower cost than conventional ENG. These technical and economical features indicate that the computerized ENG system is a very useful and convenient device for observing, recording and analyzing ENG examinations.

Audiometry, Evoked Response↗
PubMed1996

Alternations of eye movements induced by visual stimulation in a patient with acute cerebellar infarction.

We had the opportunity to investigate a patient with acute cerebellar infarction with edema that extended to the brainstem, using CT-scan and electrooculography (EOG). The purpose of this paper was to analyze the pursuit eye movements, saccades, optokinetic nystagmus (OKN) and fixation-suppression of the caloric test in an acute cerebellar infarction and on CT-scans to evaluate the connections between eye movements and lesions in the vestibulocerebellum. At the onset of infarction, data of the eye movements suggested that the lesioned area involved the bilateral dorsal pontine tegmentum and bilateral cerebellum, although the left side was predominantly impaired, as judged from the CT-scans. After more than 3 weeks from onset, deviation of the fourth ventricle and compression to the brainstem due to edema were not observed. Nevertheless, the parameters of conjugate eye movements that were analyzed had not recovered completely. This suggests that impairment of a neural integrator may still exist.

Acute Disease↗
PubMed1996

["High jugular bulb": clinical feature, radiographical findings and differential diagnosis, a case report].

Anatomically, the top portion of the jugular bulb lies just below the floor of the hypotympanum. In rare instances, it can protrude upward and elevate the floor of the hypotympanum thus placing it in the middle ear. Such a case is called high jugular bulb. This anatomical variation has been found in 3.5% to 6% of the temporal bones studied in several reports. But, clinically, only 43 cases have been reported, because in most cases they are asymptomatic. A 17-year-old female was hospitalized with right hearing disturbance and dizziness. Neurootological examination revealed sensory neuronal hearing disturbance. A caloric test was scaled out. Axial bone window CT scan demonstrated an enlarged jugular bulb and an extended upward projecting hypotympanum. MRI indicated flow void in the same region. Retrograde jugulography has been the most useful method for diagnosis but we were able to diagnose it by noninvasive MR angiography. High jugular bulb is an unfamiliar disease entity for neurosurgeons, but we should remember that it is one of the differential diagnosis for c-p angle regions or jugular foramen regions.

Adolescent↗
PubMed1996

[Dissociated adduction nystagmus in a patient with hereditary spinocerebellar degeneration].

A 66-year-old woman with a 10 years' history of autosomal dominant hereditary spinocerebellar degeneration developed an atypical nystagmus. Neurological examination revealed cerebellar ataxia, absent tendon reflex, supranuclear upward gaze palsy, saccadic pursuit and nystagmus. Nystagmus was a dissociated type and appeared only in lateral gaze and the amplitude was prominent in adducting eyes. Brain MRI showed cerebellar hemispheric and vermal atrophy, and pontine atrophy. Neuro-otological examination revealed normal caloric test, but impaired optokinetic nystagmus and visual suppression test. The dissociated adduction nystagmus of this case may correspond to gaze evoked nystagmus and latent hypofunction of the abducens motor neurons.

Aged↗
PubMed1996

[Clinical examinations in Usher's syndrome].

In this paper we are showing the results of clinical examinations in the family in which three siblings had the following symptoms: congenital deafness and nyctalopia. Clinical examinations including genetic counseling, audiometry, caloric test, Flash ERG, perimetry, computer tomography revealed total deafness, no vestibular function, and an advanced stage of retinitis pigmentosa. On the basis of clinical results, we determined the correct diagnosis: autosomal recessive Usher's syndrome-type 1. Diagnosis of the syndrome enables qualification of prognosis, complications, possibility of treatment and the risk of having the disease in the next generations. Early identification of the presence of Usher's syndrome can help in the formulation of an appropriate educational and training program. It seems purposeful that all patients with hearing loss should be examined by ophthalmologists.

Abnormalities, Multiple↗
PubMed1996

[Equilibrium and auditory disorders in patients affected by HIV-1].

It is thought that about 10% of the patients with advanced human immunodeficiency virus (HIV) infection have otoneurological symptoms, although up to 41% of these patients have general otorhinolaryngological symptoms. The otological changes may be divided into those of balance and those of hearing, to improve classification, although these symptoms are often to be found together in the same patient. We studied 30 seropositive patients with stage II and stage III disease, carrying out studies of oculomotricity, electronystagmography and audiometry (both conventional and high frequency). Oculomotricity changes were seen in 27% of the patients, whilst the caloric test were mainly normal. Conventional audiometry was normal, but high frequency audiometry showed neurosensorial deafness in 23% of the patients. These findings indicate probable changes in the vestibular and oculomotor pathways, with little change in the peripheral sensor for balance.

Acquired Immunodeficiency Syndrome↗
PubMed1997

[Illness-specific control issues in patients with vertigo as the main symptom].

The study explored the relationship between health locus of control and anxiety in 90 patients with the chief complaint of dizziness/vertigo. The patients were subjected to a neurological examination, including standardised history, physical examination, electronystagmography with caloric testing and posturography, auditory and visually brainstem-evoked responses, masseter reflex, vertebrobasiliar transcranial Doppler, optional: cranial imaging (CCT/MRI), cardial diagnostic, and a psychiatric-psychodynamic examination (including psychometric tests: STAI-G X2, KKG, SBA-S). The whole group of patients (psychogenic and organic dizziness) had a specific pattern of health locus of control: "double health external" (Type IV-Wallston and Wallston 1982). Patients with psychogenic dizziness showed a higher score of external locus of control (chance) compared with the patients with organic dizziness. High anxiety scores were accompanied by high scores of external locus of control (powerful others and chance) above all in the patients with psychogenic dizziness. Implications for therapy are discussed.

Adolescent↗
PubMed1998

[Intra-labyrinthine schwannomas: a report of two cases].

Intralabyrinthine schwannomas are rare tumors of vestibule, cochlea, semicircular canals, or some combination of these three. In the past, they have been found at autopsy or as incidental finding at surgery. Since the advent of magnetic resonance imaging (MRI) with intravenous gadolinium contrast, the preoperative diagnosis is possible. We report two cases of intralabyrinthine schwannoma: one case of intralabyrinthine schwannoma extended into the internal auditory canal (IAC), a second case of tumor restricted to the vestibule. No characteristic clinical presentation of this tumor is reported in the literature. In patients with vestibular weakness (vertigo and no response of caloric testing), MRI with gadolinium contrast can make the diagnosis of intravestibular tumor. In patients with the more common IAC acoustic neuromas, MRI can demonstrate extension of tumor into the labyrinth; diagnosing this extension preoperatively is important to plan surgical treatment.

Adult↗